Washington: Latest in the series of bombshell reports, the Edward Snowden documents have now revealed that the US agency National Security Agency traces over five billion cellphones everyday, mapping the relationship among the various cellphone users based on their location.

According to a report released by the Washington Post, the US agency accumulated humongous amount of location data everyday by tapping into cables that join mobile networks around the world.

Other than foreign nationals, the cellphone users whose location is being tracked by the NSA include millions of Americans who travel abroad.

The NSA, according to the report, used a software programme called CO-TRAVELLER, which churns through the vast location data of billions of cellphone users and establishes the "patterns of relationships between them by where their phones go".

"That can reveal a previously unknown terrorist suspect, in guilt by cellphone-location association, for instance," the report adds.

As the location data belongs to a huge sea of people, including unsuspicious ones, the NSA keeps with it a whopping amount of data running into 27 terabytes, so that it might use it if necessary later.

Clarifying over the issue, the general counsel of the Director of National Intelligence, Robert Litt, has said that the collection of bulk location data of US nationals is not done "intentionally".

However, when NSA Director Keith Alexander testified before Congress earlier, he had confessed that his agency ran tests in 2010 and 2011 on US cell-site data samples to check if it was technically feasible to feed such data into NSA systems, the Washington Post report adds.

However, the NSA Director had clarified that such data was never used for intelligence purposes and was also reported to congressional intelligence committees.

The latest expose can refuel the indignation within the US over the privacy concerns of American citizens.

The US is already reeling from the earlier Snowden revelations that have almost threatened its ties with allies like Germany, France, Spain, etc.